public class OuterClass {
    private String language = "EN";
    private String region = "China";

    //内部类可以直接访问外部类的私有变量
    public class InnerClass {
        public void printOuterClassPrivateFields() {
            String fields = "language =" + language + ";region =" + region;
            System.out.println(fields);
        }
    }

    public static void main(String[] args) {
        OuterClass outer = new OuterClass();
        OuterClass.InnerClass inner = outer.new InnerClass();
        inner.printOuterClassPrivateFields();
    }
}